Method for increasing the number of chinensis heading by staggered water and nitrogen regulation before wintering

Abstract

The invention discloses a method for increasing the number of ramie heads by regulating water and nitrogen at different times before wintering. The method comprises the following steps: selecting a medium-density ramie grassland, selecting physiologically neutral fertilizers such as urea with a nitrogen content of 46%, and applying nitrogen at a rate of 100 kg / ha during the post-fruiting nutritional period. ‑1 Pure nitrogen. Apply nitrogen fertilizer once in the early post-fruiting nutritional period. If there is no rainfall during the fertilization period, water should be added immediately after fertilization. Before the soil freezes, sprinkle or flood water once to moisten the surface 0-30cm of the soil. A single mowing can be performed before nitrogen application. After nitrogen application and before wintering, grazing disturbance should be avoided. Normal grazing can be carried out from wintering to greening the following year. After greening, grazing, mowing and other management activities should be avoided. Depending on the production conditions of the Leymus chinensis grassland, seeds can be harvested normally in late July. This method proposes for the first time the management measure of staggered nitrogen and water regulation during the post-fruiting nutritional period to increase the number of headings per unit area of ​​the perennial rhizome grass Leymus chinensis the following year, with an increase of 1.6 times compared to conventional nitrogen application, thereby achieving the goal of significantly increasing production.

Description

Technical Field

[0001] The invention belongs to a perennial rhizome grass seed production technology, and specifically relates to a method for significantly increasing the number of headings per unit area in the following year by applying nitrogen in the early post-fruiting nutritional period and watering before the soil freezes, thereby increasing the yield of sheep fescue seeds. Background Art

[0002] Leymus chinensis is a rhizomatous perennial grass belonging to the genus Leymus. As the dominant species in saline-alkali grasslands in Northeast my country, it possesses wide adaptability and ecological tolerance to cold, drought, and salinity. It not only plays a vital role in soil and water conservation and ecological restoration, but also boasts high nutritional value and good palatability, making it a key forage grass in my country. In recent years, with the rapid development of national ecological construction and pastoralism, the market has urgently needed large quantities of Leymus chinensis seeds. However, the average heading rate of Leymus chinensis is only approximately 20%, which has prevented significant increases in seed yield and has become a technical bottleneck restricting seed production.

[0003] Early studies believed that the seed yield of Leymus chinensis was mainly determined by the number of grains per ear and the thousand-grain weight. Therefore, increasing the fruit set rate and thousand-grain weight is considered to be the main way to increase seed yield. Nitrogen application is the most critical measure to increase crop yield. The traditional method of application in Leymus chinensis seed production is a one-time application from the flowering to the filling period. However, due to the limited increase in the fruit set rate and thousand-grain weight, the final seed yield still cannot achieve a breakthrough. After nearly ten years of in-depth research, the applicant team found that the number of ears per unit area of ​​the rhizome grass Leymus chinensis is the most critical seed yield component. In artificial Leymus chinensis grasslands with moderate density (<1200 plants m -2 ) When nitrogen fertilizer is applied in autumn, the number of headings in the following year can be increased, but the increase in the number of headings is still not high. The applicant team further found that the promoting effect of nitrogen application in autumn on the number of headings is mainly related to the number of underground buds and the reproductive reversal phenomenon of autumn tillers during the wintering period. How to increase the number of autumn tillers and reduce the reproductive reversal rate of autumn tillers has become a key bottleneck to overcome the low heading rate.

[0004] Based on the above analysis, the present invention proposes a method to increase the number of tillers and reduce the reproductive reversal ratio by staggered water and nitrogen application before wintering, thereby increasing the number of ears of Leymus chinensis in the following year, in order to solve the above technical problems. Summary of the Invention

[0005] In view of the above shortcomings, in order to increase the seed yield of Leymus chinensis grassland, the present invention provides a staggered regulation method for applying nitrogen fertilizer in the early post-fruiting nutritional period (early August) and watering before the soil freezes in the Songnen grassland in Northeast China, based on the conclusion that the key yield component factor limiting Leymus chinensis seed yield is the number of headings. This method significantly increases the number of headings per unit area in the following year, thereby achieving the purpose of significantly increasing the seed yield of Leymus chinensis. The present invention is achieved by the following technical means:

[0006] Methods for regulating water and nitrogen application at different times before wintering to increase the number of ramie headings include:

[0007] (1) Selection of Leymus chinensis grassland

[0008] The grassland should be of medium density, i.e. the density is 700-1200 plants m -2 Pure artificial or natural Leymus chinensis grassland with a coverage rate greater than 80%.

[0009] (2) Fertilizer type and dosage

[0010] Nitrogen fertilizers should be physiologically neutral fertilizers such as urea with a nitrogen content of 46%. The appropriate nitrogen application rate during the post-fruiting period is 100 kg / ha of pure nitrogen.

[0011] (3) Nitrogen water control time and method

[0012] Apply nitrogen fertilizer once during the early post-fruiting vegetative period (early August). If there is no rainfall during this period, water should be added immediately after fertilization to facilitate the dissolution of the nitrogen fertilizer into the soil. Fertilization should be broadcast. Before the soil freezes, when the average daily temperature is 3-5°C and the soil freezes at night but thaws during the day, apply a single spray or flood irrigation to moisten the top 0-30 cm of soil, equivalent to 20-40 mm of rainfall.

[0013] (4) Management before and after nitrogen application

[0014] A single mowing can be performed before nitrogen application. After nitrogen application and before wintering, grazing disturbance should be avoided as much as possible. Normal grazing is permitted from wintering until the next greening period. After greening, grazing, mowing, and other management activities should be avoided.

[0015] (5) Seed harvesting

[0016] According to the production conditions of the Leymus chinensis grassland, the seeds can be harvested normally in late July.

[0017] The beneficial effects of the present invention are:

[0018] This method, for the first time, proposes a management measure that uses staggered nitrogen and water application during the post-fruiting nutrient period to increase the number of headings per unit area and interannual yield stability in the following year's perennial rhizome Leymus chinensis, thereby significantly and steadily increasing seed yield. This method can more than double the number of headings per unit area compared to conventional nitrogen application, resulting in excellent economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Apply nitrogen 100 kg ha in the early post-fruiting vegetative period -1 Under these conditions, the number of headings per unit area increased the following year when watering was applied at 20 mm and 40 mm before wintering. Nitrogen application increased the number of headings per unit area by 0.47 times compared to no nitrogen application. However, under staggered watering, 20 mm watering increased the number of headings by 1.6 times compared to nitrogen application alone, a highly significant effect. DETAILED DESCRIPTION

[0020] The specific steps and conditions of the present invention are further described below:

[0021] Methods for regulating water and nitrogen application at different times before wintering to increase the number of ramie headings include:

[0022] (1) Selection of Leymus chinensis grassland

[0023] Choose medium density, that is, density of 700-1200 plants / m 2 Pure artificial Leymus chinensis grassland or high-purity natural Leymus chinensis grassland. On the natural grassland, there should be no tall weeds.

[0024] (2) Staggered nitrogen and water control method

[0025] ① Fertilizer type, dosage, application time and method

[0026] The soil in Songnen Leymus chinensis grasslands is soda saline-alkali soil, with high levels of neutral salts such as NaCl and Na₂SO₄, and alkaline salts such as Na₂CO₃ and NaHCO₃. The soil pH typically ranges from 8 to 10. Therefore, nitrogen fertilizers with a physiologically neutral nitrogen content of 46%, such as urea, should be used. During the post-fruiting vegetative period, a nitrogen application rate of 100 kg / ha of pure nitrogen is recommended.

[0027] Fertilization should be applied during the early post-fruiting vegetative period, before the underground buds of Leymus chinensis begin to sprout in large numbers in early August. Fertilization should be broadcast. Before fertilization, choose a time with a high probability of rainfall. If no rainfall occurs by mid-August, artificial watering should be applied. A small amount of water (equivalent to 5-10 mm of rainfall) should be added to allow nitrogen to dissolve into the soil.

[0028] ②Watering time, amount and method

[0029] Before the soil freezes (early November), water the sedges that have been treated with nitrogen fertilizer. Water at a rate equivalent to 20-40 mm of precipitation, soaking the top 0-30 cm of soil thoroughly. Watering can be done based on the soil's temperature. Choose sprinkler irrigation or flood irrigation when the average daily temperature is 3-5°C and the soil freezes overnight but clears during the day.

[0030] (3) Management before and after nitrogen and water regulation

[0031] Before nitrogen application, mow the grassland once in late July, leaving a stubble height of 5 cm. After mowing, nitrogen application can proceed as normal. Minimize disturbances such as vehicle traffic and grazing between nitrogen application and soil freezing and watering. If grazing is necessary, it should be light. Moderate grazing is sufficient from the time the soil is completely frozen until the next greening back. Importantly, all grazing and mowing activities should cease after the greening back.

[0032] (4) Seed harvesting

[0033] According to the production conditions of the Leymus chinensis grassland, the Leymus chinensis seeds can be harvested normally in late July.

[0034] Test example

[0035] Experiment on staggered water and nitrogen regulation in artificial grassland of Leymus chinensis

[0036] Experimental methods

[0037] The experiment was conducted in an artificial Leymus chinensis grassland sown in 2018. A randomized block design was used, with nitrogen application treatments (N0): 0 g N m -2 yr -1 、(N10):10g N m -2 yr -1 Irrigation treatment: (W0): 0 mm, (W1): 20 mm, (W2): 40 mm, 4 replicates for each treatment combination, 24 plots in total, each plot measuring 2.4 m × 1.8 m.

[0038] For nitrogen fertilization, urea containing 46% nitrogen was applied to the soil in a single application in early August 2021. A small amount of water (equivalent to 5 mm of rainfall) was sprayed simultaneously to allow the urea to blend into the soil and minimize nitrogen loss. For pre-winter irrigation, when the average daily temperature was 3-5°C and the soil was frozen at night but thawed during the day, groundwater was transported to the experimental plots using tanker trucks. Water pipes and small sprinklers were installed for irrigation, and the amount of water irrigated to the plots was controlled by flow meters.

[0039] After nitrogen application in 2021, the monthly increase in tillers of Leymus chinensis was surveyed three times from August to October. The number of Leymus chinensis seedlings that turned green in the previous autumn was counted in early May of the following year. The number of Leymus chinensis, the number of ears and the heading rate were surveyed and counted during the seed maturity period.

[0040] Key results

[0041] Under the same nitrogen application level, the number of new tillers of Leymus chinensis showed a downward trend as the months increased. Among them, under the condition of no nitrogen application (N0), the number of new tillers in August, September and October were 288 plants m -2 , 90 plants m -2 and 30 m -2 The number of new tillers in August was significantly higher than that in September and October (P<0.05). -1 Under the condition (N10), the number of newborn plants in August was 476 plants m -2 、166 strains m -2 、53 strains m -2 The number of new shoots in August and August was also significantly higher than that in September and October (P<0.05). Within the same growing month, nitrogen application significantly affected the number of new shoots (P<0.05). Compared with N0, the number of new shoots in August, September, and October under N10 treatment increased by an average of 0.66, 0.88, and 0.79 times, respectively, and the total number of shoots increased by an average of 1.70 times.

[0042] Under the same nitrogen application level, the number of Leymus chinensis turning green showed a trend of increasing first and then decreasing with the increase of irrigation amount. Among them, under N0 condition, the number of turning green when irrigating with 20mm water was 328 plants m -2 , which was 1.07 times higher than the control, and the irrigation amount of 40mm increased by 0.67 times than the control; under N10 conditions, the number of plants turning green when irrigating with 20mm water was 510 plants m -2 The total number of autumn tillers of Leymus chinensis that returned to green under N10 treatment increased significantly by 0.84, 0.67, and 0.44 times compared to no nitrogen application, respectively, under irrigation rates of 0, 20, and 40 mm (P < 0.05).

[0043] Under the N0 nitrogen application level, the number of ears of Leymus chinensis showed a trend of first increasing and then decreasing with the increase of irrigation amount. Among them, when the irrigation water amount was 20 mm, the number of ears per square meter was 260 m -2 , which increased by 1.90 times compared with the control, and the irrigation amount of 40mm increased by 0.68 times compared with the control; under the N10 nitrogen application level, the trend of first increasing and then decreasing was presented as the irrigation amount increased. Among them, the number of heading per square meter when the irrigation amount was 20mm was 341 plants m -2 , an increase of 1.63 times compared with the control, and an increase of 0.81 times compared with the control under the irrigation amount of 40 mm. Under the conditions of irrigation amount of 0 mm, 20 mm and 40 mm, the number of headings under the N10 treatment increased significantly by 0.47, 0.31 and 0.59 times compared with no nitrogen application, respectively (P < 0.05).

[0044] in conclusion

[0045] Combine Figure 1 The results showed that staggered nitrogen and water application significantly promoted the number of tillers per unit area in autumn, the number of greenings in the following year, and the number of headings. Compared with conventional nitrogen application, staggered nitrogen and water application significantly increased the number of headings per unit area in the following year, by as much as 1.6 times. In practical production, the application of this method has important guiding significance for increasing Leymus chinensis seed yield.

Claims

1. Methods for regulating the timing of water and nitrogen application before wintering to increase the number of chinensis headings include: (1) Select a grassland with an appropriate density of Leymus chinensis: 700-1200 plants / m 2 Pure artificial Leymus chinensis grassland; or natural Leymus chinensis grassland with Leymus chinensis coverage greater than 80%; (2) Staggered nitrogen and water control method: (2.1) Fertilizer type, dosage, application time and method: Nitrogen fertilizer type should be physiologically neutral fertilizer with nitrogen content of 46%; in the post-fruiting nutrient period, the nitrogen application rate should be 100 kg / ha. -1 Pure nitrogen fertilizer; Fertilization should be done in the early post-fruiting nutritional period, and during rainfall. If there is still no rainfall by mid-August, artificial watering should be carried out, and the amount of watering should be equivalent to 5-10mm of rainfall. Fertilization should be done by broadcasting. (2.2) Watering time, amount and method: Before the soil freezes, water the nitrogen-fertilized Leymus chinensis grassland when the average daily temperature is 3-5°C and the soil freezes at night and melts during the day. (3) management before and after nitrogen and water regulation; and (4) Harvest seeds.

2. The method for increasing the number of heading of Leymus chinensis according to claim 1, wherein: The amount of watering in step (2.2) is equivalent to 20-40 mm of rainfall, so that the surface 0-30 cm of soil is thoroughly wet.

3. The method for increasing the number of heading of Leymus chinensis according to claim 1, wherein: The nitrogen and water regulation before and after management in step (3) includes: Before applying nitrogen, the grassland was mowed once at the end of July, leaving a stubble height of 5 cm; After mowing, apply nitrogen normally until the soil freezes before watering.

4. The method for increasing the number of heading of Leymus chinensis according to claim 1, wherein: The time for harvesting seeds in step (4) is late July.

Images